Internal combustion engine

Abstract

An internal combustion engine includes a first intake valve, a second intake valve, an accelerator open degree sensor that detects a load state, and an ECU 26 that controls the valve opening timing of the first and second intake valves and an amount of intake gas introduced to a combustion chamber from the first and second intake valves. When a load of a vehicle increases, the ECU reduces the ratio of the amount of intake gas from, among the two or more intake valves, the second intake valve having a later valve opening timing, whereas when the load decreases, the ECU increases the ratio.

The invention claimed is: 
     
       1. An internal combustion engine comprising:
 a plurality of intake valves, respectively provided for a plurality of intake ports which are independently connected to a combustion chamber; 
 a load state sensor which senses a load state of the engine; 
 a controller which controls, based on a sensed result from the load state sensor:
 respective valve opening timings of the plurality of intake valves such that a first intake valve of the plurality of intake valves has an earlier valve opening timing or a second intake valve of the plurality of intake valves has a later valve opening timing, 
 a first ratio which is a ratio of an amount of intake gas introduced to the combustion chamber from the first intake valve to a total amount of intake gas, and 
 a second ratio which is a ratio of an amount of intake gas introduced to the combustion chamber from the second intake valve to the total amount of intake gas; and 
 
 a turbocharger having a wastegate valve, the turbocharger supercharging fresh gas on an upstream side of at least the second intake valve, wherein: 
 when the load state sensed by the load state sensor increases, the controller reduces the second ratio by increasing an opening degree of the wastegate valve to reduce the amount of intake gas introduced to the combustion chamber from the second intake valve and increasing the amount of intake gas introduced to the combustion chamber from the first intake valve, and 
 when the load state sensed by the load state sensor decreases, the controller increases the second ratio. 
 
     
     
       2. The internal combustion engine according to  claim 1 , further comprising:
 a valve timing variable mechanism configured to adjust the valve opening timings of the plurality of intake valves. 
 
     
     
       3. The internal combustion engine according to  claim 2 ;
 wherein the controller adjusts, in accordance with a change in the sensed load state, the second ratio by adjusting the amount of intake gas introduced to the combustion chamber from the first intake valve and the amount of intake gas introduced to the combustion chamber from the second intake valve. 
 
     
     
       4. The internal combustion engine according to  claim 2 ;
 wherein when the load state sensed by the load state sensor increases, the controller reduces the second ratio by separating the valve opening timing of the second intake valve from an intake bottom dead center by the valve timing variable mechanism. 
 
     
     
       5. The internal combustion engine according to  claim 1 ;
 wherein the controller adjusts, in accordance with a change in the sensed load state, the second ratio by adjusting the amount of intake gas introduced to the combustion chamber from the first intake valve and the amount of intake gas introduced to the combustion chamber from the second intake valve. 
 
     
     
       6. The internal combustion engine according to  claim 1 ;
 wherein the controller performs control to introduce to the combustion chamber intake gas having different compositions from the plurality of intake ports. 
 
     
     
       7. The internal combustion engine according to  claim 1 ,
 wherein the intake port at which the first intake valve is disposed forms one of a swirl gas flow and a tumble gas flow, and the intake port at which the second intake valve is disposed forms a remaining one of the swirl gas flow and the tumble gas flow. 
 
     
     
       8. The internal combustion engine according to  claim 1 ,
 wherein the intake port at which the second intake valve is disposed has a shape arranged to introduce intake air to the combustion chamber by a contracted flow.